Interior Lighting Systems Description and Operation

Interior Lighting Systems Description and Operation

Interior Lamps

The interior lamps consist of 2 groups, those which can dim from the instrument panel cluster lamps dimmer switch and those that can not dim.

Courtesy/Illuminated Entry Lamps

The following lamps may be manually turned ON by placing the interior lamp switch in the ON position, or by opening a door while the switch is in the AUTOMATIC position.

* The dome lamp
* Courtesy lamps

The courtesy lamp supply voltage circuit of the body control module (BCM) supplies battery positive voltage to the dome lamp, the liftgate lamps and courtesy lamps. When any door is opened, the door jamb switch contacts close providing a door open input to the BCM. The BCM then provides a B+ to the interior lamps with the switch in the AUTOMATIC LIGHT position. The interior lamps receive a ground when the switch is in the ON position.

Note: If the liftgate is opened after all the modules go to sleep, the dome light will not come on. The liftgate ajar switch input to the BCM will not wake up the BCM once it has gone to sleep, so the dome light will not come on. Once the BCM gets an input to wake it up, from remote keyless entry or a door handle, the dome light will turn on when the liftgate is opened.

If the driver inadvertently leaves any interior lamp ON, the BCM will turn it OFF after a 20 minute time-out.

The courtesy lamps will turn OFF immediately if the ignition switch is turned to the ON position or approximately 20 seconds after all doors are closed.

Door Sill Illumination

The door sill lighting is a dealer installed accessory. When the body control module (BCM) receives a signal to command the courtesy lamps ON, it applies battery voltage through the dome/courtesy lamps control circuit to the courtesy lamps. The door sill illumination receives voltage through the courtesy lamps circuit. The door sill illumination harness connector includes a power inverter which converts the battery voltage to 150 V AC (550 Hz). This AC voltage is supplied to the door sill lamps and causes them to illuminate.

Accent Lamps - Driver Door, Passenger Door and Instrument Panel

The accent lamps operate very similarly to the courtesy/illuminated entry lamps. They may be manually turned ON or OFF by placing the interior lamp switch in the ON or OFF position. If an outside door handle is lifted and a door is opened, the accent lamps will illuminate. After all the doors have been closed the accent lamps will remain illuminated approximately 15 seconds. The body control module (BCM) will then turn them OFF through the theater dimming feature. The accent lamps will also turn ON prior to any door being opened, and remain illuminated approximately 40 seconds when the driver removes the ignition key.

Unlike the courtesy/illuminated entry lamps, the intensity of the accent lighting can be controlled through use of the instrument panel dimmer switch. The accent lamps will have the same lighting intensity as the other dimmable lighting.

The driver door and passenger door courtesy lamps receive voltage and ground from the driver door switch and the passenger door switch respectively.

Keyless Entry Interior Illumination

When the BCM receives a door unlock command from the remote keyless entry transmitter, the BCM will flash the park lamps several times, illuminate the courtesy and park lamps, and illuminate the low beam headlamps at low intensity. The lamps will remain on until the ignition key is turned from the OFF position, a keyless entry transmitter door lock command is received, or after an approximate 20 seconds delay.

Interior Lamps Dimming

This group includes lamps which may dim. This group may use a combination of vacuum fluorescent illumination, LEDs and incandescent lamps.

* HVAC control module, head assembly
* Rear HVAC control module, head assembly
* Radio
* Rear seat audio
* The instrument panel cluster
* The PRNDL lamp, with the exception of the current gear select position
* Power window switches
* Various switches
* Accent lamp - driver door handle
* Accent lamp - passenger door handle
* Accent lamp - left rear door handle
* Accent lamp - right rear door handle
* Accent Lamp - console left front
* Accent Lamp - console right front
* Accent Lamp - console left rear
* Accent Lamp - console right rear
* Tube left
* Accent lamp - left instrument panel
* Accent lamp - right instrument panel

When the ignition switch is turned to the ON position, the vacuum fluorescent display, radio, turns ON at maximum brightness. When the park lamps are ON, all incandescent back lighting turn ON at the dimming level indicated by the instrument panel cluster dimmer switch. At the same time all fluorescent display displays dim to match the indicated dimming level. When the headlamp switch is placed in the PARK position, the park lamp supply voltage circuit provides an input to the BCM. The BCM then supplies voltage to the instrument panel cluster dimmer switch through the dimming control circuit. The setting of the instrument panel cluster dimmer switch determines the amount of voltage that the instrument panel cluster dimmer switch supplies to the BCM. The BCM then sends a PWM voltage to all the interior lamps. All the fluorescent display and incandescent back lighting lamps are provided a specific voltage and are then grounded. When the headlight switch is turned to the park lamp or headlamp position, all incandescent back lighting turn ON at the dimming level indicated by the instrument panel cluster dimmer switch. When the instrument panel cluster dimmer switch is moved from MIN to MAX, all fluorescent display displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the instrument panel cluster dimmer switch.

Inadvertent Power

The BCM used in this vehicle controls the lighting system through circuits that enable the interior lamps. The BCM opens these enabling circuits shortly after the ignition switch is turned OFF with no lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this period, the timer will reset itself.